Vibration reducing bearing mount in a blindstitch sewing machine



G. C. ROTH VIBRATION REDUCING BEARING MOUNT IN A Jan. 2, 1968 I BLINDSTITCH SEWING MACHINE Filed Nov. 26, 1965 4 Sheets-Sheet l Jan. Z, 1968 c. Rom 3,361,101

G. VIBRATION REDUCING BEARING MOUNT IN A BLINDSTITCH'SEWING MACHINE Filed Nov. 26, 1965 4 Sheets-$heet 2.

Rom VIBRATION REDUCING BEARING MOUNT IN A Jah. 2, 1968 I 'BLINDSTITCH SEWING MACHINE 1 Filed Nov. 26, 1965 I 4 Sheets-Sheet 3 Jan. 2, 1968 G. C. ROTH VIBRATION REDUCIN 3,361,101 G BEARING MOUNT IN A BLINDSTITCH SEWING MACHINE Filed NOV. 26, 1965 4 Sheets-$heet 4 United States Patent 3,361,101 VIBRATION REDUCTNG BEARING MQUNT IN A BLINDSTITCH SEWING MACHINE Gerald C. Roth, Bethpage, N.Y., assignor to Union Special Machine Company, Chicago, Ill., a corporation of Illinois Filed Nov. 26, 1965, Ser. No. 509,988 11 Claims. (Cl. 112-176) ABSTRACT OF THE DISCLOSURE In a blindstitch sewing machine having a looper carrying rod which is given three types of movement, namely, a longitudinal reciprocatory movement, an angular oscillatory movement, and a pivotal movement about a fulcrum adjacent the end thereof, improved driving connections from a main rotary drive shaft for imparting said various movements. Such connections include a stud which is disposed at an acute angle to the axis of said drive shaft and is given an orbital movement about the axis of said shaft. To enable high-speed operation of the machine, without the development of undue vibrations, special means are provided for retaining the outer end of the stud against vibratory movements. For this purpose, there is secured to the outer end of the stud an arm extending at right angles to the axis of the stud and having an extension which is directly aligned with the axis of the main drive shaft. This extension is journalled in a suitable bearing provided in the frame structure of the sewing machine.

This invention relates to blindstiteh sewing machines of the character involving a looper mechanism having a looper carrying rod which is given compound motions, including a longitudinal reciprocatory movement, an angular oscillatory movement and pivotal movements about a fulcrum at the end thereof which is connected with the driving means and about a fulcrum intermediate its ends.

Looper mechanisms of the character above mentioned, as heretofore constructed, have been found to run into difiiculties particularly when efforts are made to increase the speed of operation of the machine to keep up with presently desired production rates. The means for driving the looper rod, and imparting to it the various motions mentioned above have involved a driving stud carried by an angularly disposed extension of a counterweight member secured to the main drive shaft of the machine. One type of mechanism of this character is shown in the patent to Mueller, No. 2,588,274, granted Mar. 4, 1952. In that mechanism the looper driving stud in firmly but rotatably secured to the angularly disposed extension of the counterweight member. The extension referred to is inclined at an angle of about 48 to the longitudinal axis of the main shaft, and the stud is rotatably mounted in a bearing sleeve extending at an angle of 90 from the angular extension that functions as a crank arm. Connections are provided from the stud to a looper rod or carrier. An older form of such mechanism, as shown in the patent to Kelso No. 2,195,700, granted Apr. 2, 1940, has a stud fixedly secured to the crank arm, while a sleeve rotatable about said stud has been connected with a looper rod for imparting the compound movements to the latter. It has not been appreciated heretofore that it is highly desirable to provide other supporting or guiding means for the stud which imparts the desired movements to the looper carrying rod.

The connections from the stud to the looper for imparting the various types of motion to the looper rod, in both types of mechanism described above, have been in the form of a member carried by the stud, either fixedly or rotatably, at a point intermediate its free outer end and it point of connection with the crank arm. It will be 3,361,101 Patented Jan. 2, 1968 appreciated that in view of the disposition of the stud in relation to the main drive shaft it is carried around an orbital path, and by virtue of the mode of mounting the looper rod and the connections from the stud to the latter, the rod is oscillated through a suitable angle as it is being reciprocated in a longitudinal direction, and the end of the rod which is connected with the element carried by the stud causes a pivotal movement of the rod about the two fulcrums mentioned above.

It has been found that various difficulties are encountered in the operation of the looper carrying rod, and hence the looper connected therewith, when attempts have been made to speed up the operation of the machine. These difficulties have included distortion and over-throw of the looper mechanism, vibration and undesirable noises generated in the course of operation of the mechanism, excessive wear upon various bearing surfaces, lack of uniform stitch formation, and in some instances the striking of the needle employed in the stitch forming mechanism, which results in bending of the needle and sometimes breakage of the needle.

A primary purpose of the present invention has been to provide a drive for a looper of the character discussed above which will eliminate or at least greatly minimize the difiiculties mentioned. Toward the foregoing end, an important feature of the invention is a different mode of assembly of the stud and its associated parts on the crank arm.

An even more important feature of the invention is the provision of a special bearing arrangement, hereinafter sometimes referred to as an outboard bearing, cooperating with the outer end of the angularly disposed stud which is secured to the angularly disposed portion of the counterweight element. This bearing includes an arm secured to the outer end of the stud and disposed parallel with but spaced outwardly from the crank arm extension of the counterweight member. The arm in turn carries, integrally or otherwise, a cylindrical or spherical extension which is axially alined with the main drive shaft of the machine. This cylindrical or spherical extension is adapted for rotation in a bearing mounted in an end wall portion of the frame of the machine which extends in a plane perpendicular to the axis of the main drive shaft of the machine. By virtue of this support for the outer end of the stud on which the looper driving sleeve is rotatably mounted, the tendency of the stud to vibrate at high speed operations of the machine, with the resulting difficulties discussed above in relation to the prior art constructions, is eliminated.

With the foregoing features and advantages of the invention in mind, a preferred embodiment of the invention will now be described in detail in reference to the accompanying drawings, of which:

FIG. 1 is a view, partially in plan and partially in horizontal cross-section showing that portion of a blind-stitch sewing machine which embodies the novel features of the invention;

FIG. 2 is an elevational view of the machine, with a portion of the upper structure shown in vertical section taken along the broken line 2-2 of FIG. 1 in the direction indicated by the arrows;

FIG. 3 is a detail view showing a portion of the machine in vertical section taken along the broken line 33 of FIG. 1 in the direction indicated by the arrows;

FIG. 4 is an elevational view of a portion of the upper structure of the machine, in the region indicated by the line 4-4 of FIG. 1;

FIG. 5 is a detail view, partially in plan and partially in cross-section, showing the connection of the looper driving sleeve, the stud upon which it is mounted and the line 66 of FIG. 1, showing the means for supporting the forward end of the looper operating rod;

FIG. 7 is a cross-sectional view taken along the line 77 of FIG. 6 and FIG. 8 is a view, partially in elevation and partially in section, taken along the line 8-8 of FIG. 7.

The invention as illustrated in the drawings is shown as applied to a machine having the general construction of that disclosed in the patent to Mueller, No. 2,588,274, granted Mar. 4, 1952. It incorporates certain features embodied in the machine disclosed in the Roth et al. application Ser. No. 309,019, filed on Sept. 16, 1963, now Patent No. 3,288,094, granted Nov. 29, 1966. Thus the machine embodies a main drive shaft 10 (FIG. '1) extending longitudinally of the upper arm structure 11 of the frame of the machine at its outer end, at the right in FIG. 1, the shaft 10 has secured thereto a combined hand wheel and pulley 12 by which the drive shaft may be turned, either through a belt connected with a suitable power source or manually by the operator through rotation of the hand wheel. Shaft 10 is suitably journaled in bushings 13 and 14- adjacent its left and right ends, respectively. At its left end the shaft extends into the interior of a forwardly and downwardly extending arm 15 of the machine frame. The latter houses various members of the driving connections from shaft 10 to a looper and other driven mechanism of the machine.

The stitch forming mechanism of the machine includes a curved needle 16 (FIG. 2) secured to a needle carrying arm 17 which has a split hub portion that is clamped by means of a screw or bolt 18 to a rock shaft 19 suitably journaled in and extending longitudinally of the arm 15 of the frame structure. Appropriate connections are provided from the main drive shaft lit to the rock shaft 19 for rocking the latter upon rotation of the drive shaft. These connections, as shown in FIGS. 1 and 2, comprise a partially spherical eccentric 20 secured to a reduced portion of the shaft 10 at its left end (FIG. 1). Cooperating with the eccentric is a strap 21a at the lower end of a link 21 which extends upwardly at a suitable angle from the eccentric 20 and has a strap portion 211) at its upper end cooperating with a spherically surfaced pin extending from an arm 22 which is clamped to the left end (FIG. 2) of the shaft 19. Through the connections just described, the shaft 19 and hence the curved needle 16 will be oscillated in a manner to carry the pointed end of the needle into and out of a node of work presented in its path. Since the node forming mechanism may be of the conventional type employed in blindstitch sewing machines, and which is more fully disclosed in the above-mentioned Roth et al. application, it need not be described here. The node former is illustrated, however, in FIG. 1 at 23.

The work to be stitched is advanced along the work supporting surface in the stitching region of the machine by a top feed mechanism which may be of a conventional construction. Reference may be had to the patents to Mueller, No. 2,109,014, granted Feb. 22, 1938, and Kelso, No. 2,195,700, granted Apr. 2, 1940, for a suitable type of top feed mechanism that may be employed. It may include a feed bar 24 (FIG. 1) having a strap portion 24a surrounding an adjustable eccentric secured to the main drive shaft 10. This eccentric may include an element 25 cooperating with the strap portion 24a of the feed bar, and which is mounted for angular adjustment about a portion of a second element 25a of the adjustable eccentric to vary the extent of feed imparted to the feed dog and hence the length of the stitches to be produced. Conventional means may be provided for varying the relative angular relationship between the elements 25 and 25a of the adjustable eccentric to determine the stitch length to be provided. At an intermediate point the feed bar is pivotally connected with a supporting link 24b.

The looper mechanism of the machine will now be described in some detail. It involves a thread engaging element or looper 26 secured by a screw 26a to an upwardly and forwardly extending portion 27a of a looper rod 27 (PEG. 2). The length of this rod may be varied slightly by the extent to which a threaded portion 27b at its left end is screwed into a shank portion of a forked connecting element 2% having spaced arms 28a and 28]) adapted for cooperation with the driving means to be explained. Adjacent its forward end, i.e. the right end as shown in FIG. 2, the looper rod is provided with a spherically surfaced portion 280 which cooperates with a spherical surface provided in a guiding or retaining arm 29 having its upper end clamped by a screw 29a to a stud 30. Stud 30 has an enlarged head 30a at its opposite end, and this together with arm 29 serves to retain it against longitudinal movement and yet enable it to turn within a bearing element 31 mounted in an extension 15a of the forwardly extending arm of the frame. For details of this construction reference may be had to FIGS. 6, 7 and 8 of the drawings.

The bearing element 31 has an eccentric portion 31b and a knurled head 31c. By manual turning of the knurled head 310 the position of the axis of stud 30 may be varied slightly to position the looper in desired relation to the needle path and the work supporting surface of the machine. When the bearing has been turned into the desired position it may be clamped in such position by a screw 32.

The forked end of element 28 carries a pin 33 (FIGS. 1 and 2) by which said element is pivotally connected with an extension 34a of a sleeve 34. This sleeve is mounted for free turning movement about a stud 35, through the intermediary of needle bearing units 36. A bronze bearing may be used in lieu of the needle bearings if desired. Stud 35 is fixedly secured to an angularly disposed crank arm portion 37a of a counterweight member 37 that is secured to the shaft 10, adjacent its left end (FIGS. 1 and 5) by set screws 38. Portion 37a of the counterweight is preferably at an angle of about 48 to the longitudinal axis of the shaft 10. This places the stud 35 at an angle of about 42 to the axis of the shaft 10.

In order to reduce to a minimum the frictional resistance to the turning of the sleeve 34 about the stud 35 certain elements are provided at opposite sides of the sleeve 34 for receiving the thrust in both directions, while maintaining the sleeve against any movement longitudinally of the stud 35 with a minimum of resistance to turning of the sleeve relative to the stud. Of course the needle bearings or the like indicated at 36, and described above, minimize the frictional resistance to rotation of the sleeve about the stud. For the thrust receiving purposes there is provided at the upper end of sleeve 34 (FIG. 5) a thrust washer 39, and a similar thrust washer 40 is provided at the lower end of the sleeve. Spaced slightly outwardly from the thrust washers 39 and 40 are thrust washers 41 and 42, respectively. Between thrust washers 39 and 41 there is mounted about the stud 35 a thrust bearing member 43 preferably provided with ball elements as shown in FIG. 5. Similarly, between thrust washers 40 and 42 there is provided about the stud 35 a thrust bearing member 44 which is also preferably provided with ball bearings. Outwardly of the crank arm portion 37a of the counterweight there is a lock washer 45 which is held firmly against the outer face of the crank arm by means of a nut 46 having screw threaded engagement with the lower end of stud 35. This lock washer serves to prevent the nut 46 from working loose in the course of operation of the machine. Outwardly of the thrust washer 41 there is provided a nut 47 having screw threaded engagement with a thread portion of stud 35, and a lock nut 48 having similar screw threaded engagement with the stud 35 serves to lock the parts in their assembled relation. It will be understood that the assembly is such as to firmly retain the stud 35 on the crank arm portion 37a with no longitudinal play of the stud or the sleeve 34, but without exerting an objectionable pressure against the thrust bearings and washers described.

An important, novel aspect of the present invention is the provision of a crank arm 49 at the upper end of the stud 35 (FIG. 5). This crank arm is firmly secured to the upper end of stud 35 by means of a set screw 50, preferably having a pointed inner end which cooperates with a conical recess 51 in the surface of the reduced diameter upper end portion of the stud 35. Crank arm 49 is disposed in parallel relation to the crank arm portion 37a of the counterweight member 37 and it has an angularly disposed cylindrical extension 52 which has its longitudinal axis alined with that of the main drive shaft 10. The cylindrical extension 52 is preferably journaled by means of needle bearings 53 (FIG. 1) in an end wall 54 of the frame structure of the machine. This end wall of the frame may either be formed integrally with the downwardly and forwardly extending arm 15 of the frame or it may be detachably connected with the latter by means of screws 55. Through the use of the detachable connection of the endwall with the frame structure, access is more readily provided to the interior mechanism, thus facilitating the adjustment and repair or replacement of certain of the parts.

While it is considered highly desirable to have the extension 52 journaled in the end wall 54 through the intermediary of needle bearings, as shown in FIG. 1, such needle bearings may be replaced by a bronze bearing or by a ball joint. If a ball joint is employed, the extension 52 will be of spherical form and adapted to cooperate with a spherical surface provided in the end wall 54 of the frame. In this event the end wall 54 should be provided with a bearing element formed in two sections to permit the mounting thereof around the ball extension of the crank arm 49, and suitable means will be provided for retaining the spherically surfaced bearing element within an opening in the end wall of the frame. An advantage of the ball type joint connection of the crank arm 49 with the end wall 54 is that it will automatically take care of any slight misalinement of the bearing for the lateral extension of crank arm 49 with the aXis of the main drive shaft 10.

It has been found that the provision of the bearing support for the outer end of the stud 35 reduces to a minimum the noise and vibration incident to the high speed operation of the machine. Such elimination of vibration insures the proper cooperation of the looper with the needle and the thread carried thereby, and avoids. the danger of breaking the needle and of producing nonuniform stitches in the course of high speed operation of the machine.

As in the blindstitch sewing machines disclosed in the patents referred to hereinabove, the looper rod is given the compound movement described, including a longitudinal movement, a turning movement through an angle of about 90, and a tilting movement about the retaining arm 29, upon each revolution of the main drive shaft of the machine. In this way the looper is given its desired movements to seize a loop of thread from the oscillatory needle, then turn this loop into a position in which it may be readily entered upon the next work engaging movement of the needle, and the looper is then retracted longitudinally and rotated back to its initial position to be ready for a repetition of the loop seizing and turning operations and the tilting of the looper rod about the fulcrums mentioned.

Provision is preferably made for insuring proper lubrication of the various bearing surfaces incorporated in the machine. This may be accomplished by providing for the delivery of a lubricant spray or droplets into the regions requiring lubrication. Such means include, for example,

the provision of a lubricant receiving opening 56 (FIG.

3) into which the operator or maintenance man may introduce lubricant from which it is delivered through a pocket 57 and an opening 58 to the bearing for the drive shaft 10. Within the head of the machine, there may also be provided a tube 59 through which lubricant may "be supplied to be delivered to various parts of the operating devices within the head. Such lubricant may be delivered, for example, to an opening 60 in the sleeve 34 (FIG. 5) from which it is supplied to the needle bearing units 36.

While a preferred embodiment of the invention has been described in considerable detail, and certain possible modifications have been suggested, it will be understood that the construction may be further modified in a way to embrace the highly advantageous features of the invention to be hereinafter set forth in the appended claims.

What is claimed is:

1. In a blindstitch sewing machine having a frame structure, a main rotary drive shaft and stitch forming mechanism including a looper carrying rod adapted to be reciprocated longitudinally, turned angularly through a predetermined arc and tilted pivotally about at least one fulcrum, and connections from said drive shaft for imparting all of such movements to said looper carrying rod, the combination which comprises a member secured to said drive shaft for rotation therewith, a stud fixedly secured to said member outwardly of the axis of rotation of said shaft and positioned at an acute angle toward said axis, a sleeve mounted on said stud for angular movement about the axis of said stud, means for pivotally connecting said rod with said sleeve, a crank arm rigidly connected with said stud, said arm extending perpendicularly to said stud and having an angularly projecting portion at the outer end thereof disposed in alignment with the axis of said drive shaft, and fixed bearing means carried by said frame structure in which said angularly extending portion is journaled.

2. In a blindstitch sewing machine as set forth in claim 1, said angularly projecting portion of said crank arm being cylindrical in form, and said fixed bearing means comprising rotatable bearing means cooperating with said angularly projecting portion.

3. In a blindstitch sewing machine as set forth in claim 1, said angularly projection portion of said crank arm having a spherical configuration, and said fixed bearing means having a spherical bearing surface with which said projecting portion cooperates.

4. In a blindstitch sewing machine as set forth in claim 1, retaining means carried by said stud for retaining said sleeve against longitudinal movement in relation to said stud.

5. In a blindstitch sewing machine as set forth in claim 4, said retaining means comprising thrust bearing means adapted to provide minimum resistance to the turning of said sleeve about said stud.

6. In a blindstitch sewing machine as set forth in claim 5, said retaining means also comprising adjustable nut elements for holding said sleeve and said thrust bearing elements in a substantially fixed position longitudinally of said stud.

7. In a blindstitch sewing machine as set forth in claim '6, said thrust bearing means comprising a ball bearing thrust resisting member disposed adjacent each end of said sleeve.

8. In a blindstitch sewing machine having a frame structure, a main rotary drive shaft and stitch forming mechanism including a looper carrying rod adapted to be reciprocated longitudinally, turned angularly through a predetermined arc and tilted pivotally about at least one fulcrum, and connections from said drive shaft for imparting all of such movements to said looper carrying rod, the combination which comprises a member secured to said drive shaft for rotation therewith, said member having a portion thereof inclined at an acute angle to the axis of said drive shaft, a stud carried by and disposed at right angles to said portion of said member, connections from said stud adapted to impart all of said movements to said looper carrying rod, and means journalled in said frame structure cooperating with the free end of said stud for retaining the same against vibrating movements thereof.

9. In a blindstitch sewing machine as set forth in claim 8, said means cooperating with the free end of said stud comprising a member carried by said stud and having an extension axially alined With the axis of said drive shaft, and fixed bearing means carried by said frame structure cooperating with said extension.

10. In a blindstitch sewing machine as set forth in claim 9, said bearing means cooperating with said extension comprising a needle bearing unit.

11. In a blinds titch sewing machine as set forth in claim 9, said extension of said member carried by the free end of said stud having a substantially spherical journalling portion, and said fixed bearing means having a spherical surface cooperating with said spherical journalling portion.

References Cited UNITED STATES PATENTS 2,195,700 4/1940 Kelso 112177 2,588,274 3/1952 Mueller 112-476 2,894,470 7/1959 Buono 112-178 3,105,450 10/1963 Taylor 112-178 3,288,094 11/1966 Roth et a1. 112-178 HERBERT F. ROSS, Primary Examiner. 

